ROCHESTER — A Somersworth woman was airlifted to Maine Medical Center Thursday night after she was struck by a vehicle that fled the scene.

Police say that just before 6 p.m. Thursday, 25-year-old Katherine Littlefield, of Somersworth, was in the crosswalk on North Main Street when a southbound vehicle, described as a black Nissan Pathfinder, struck her and left the scene.

The incident occurred near the intersection of Pine Street.

After being struck, Littlefield was thrown to the ground south of the intersection, where she lay until bystanders and the police could attend to her, according to a statement released by police Thursday evening.

Fire Capt. Mark Avery said shortly after the accident Littlefield suffered injuries that are not believed to be life-threatening. He said she had what appeared to be serious injuries to her legs.

At approximately 6:05 p.m., officials requested a DHART helicopter, and Littlefield was transported to Skyhaven Airport, where she was then airlifted to Maine Medical Center, according to police.

A portion of North Main Street was closed for approximately 30 minutes, as EMS attended to Littlefield's injuries and the police investigated the scene.

The collision remains under investigation.

Police ask that anyone who may have information that could assist with this investigation to call Officer Kusneirz at the Police Department at 330-7128. Alternatively, those with information can provide tips and remain anonymous by calling the Rochester Crimeline at 335-6500 or Text to: CRIMES (274637) and in the body of the text write: TEXT4CASH + the tip. Cash rewards are offered for information that leads to an arrest.

Rochester police remind drivers that when pedestrians are in a crosswalk that is not controlled by a crossing light, drivers are required to stop for them under the statute RSA 265:35.